Isolation, characterization and evaluation of endophytic fractions of Centella asiatica Linn. (leaves) for Invitro antioxidant activity

Abstract

In the present investigation, we have carried out the isolation of fungal endophytes from Centella asiatica Linn leaves followed by fermentation and extraction of fungal endophytes with non-polar solvents such as chloroform, ethyl acetate and n-butanol. Preliminary phytochemical investigation of endophytic crude fractions of leaves were also determined to detect the presence of primary and secondary metabolites followed by invitro free radical scavenging activity by reducing power, DPPH and hydroxyl radical assay. The chloroform fungal endophytic fractions were subjected to column chromatography by gradient elution technique for isolation of possible secondary metabolite. Reducing power of endophytic extracts of C. asiatica Leaf (CAL-1) (50-450µg/ml) increased with increase in concentration. Reaction with DPPH radicals of CAL-1 showed good scavenging activity. The IC50 values for Ascorbic acid, chloroform extract, ethyl acetate extract and n- butanol extract were found to be 30.33 µg /ml, 66.58 µg/ml, 79.33 µg /ml and 96.39 µg/ml respectively. In hydroxyl radical assay, The IC50 values for mannitol, chloroform extract, ethyl acetate extract and n- butanol extract were found to be 121.06 µg / ml, 141.21 µg/ml, 181.80 µg/ml and 189.90 µg/ml respectively. The endophytic crude fractions of ethyl acetate exhibited potent antioxidant activity as compared to other fractions. Hence, ethyl acetate fungal endophytic fractions of Centella asiatica Linn leaves can be employed as a potential antioxidant in the prevention of oxidative stress caused by the free radicals.